Russian President Dmitry Medvedev has offered full support for envoy Kofi Annan's peace mission in Syria, saying it may be the last chance to avoid a "prolonged and bloody civil war".

The governent in Moscow urged Mr Annan to work with both the Syrian government and opposition to end the violence.

Mr Annan has been seeking to persuade Russia to take a firmer stance against President Bashar al-Assad's government.

He will later go to China which has also usually backed Syria at the UN.

As clashes continue, Human Rights Watch has accused Syrian government forces of using civilians as human shields.

Activists reported further bombardments and casualties on Sunday in the Homs area, killing at least five people.

Shelling was also reported in Hama, and tanks were seen in the streets of the southern town of Nawa, the Local Coordination Committees said.

More than 50 people were reported to have been killed in shelling or shooting by the security forces on Saturday, many of them in Homs.

The UN says the conflict has cost more than 8,000 lives since it began a year ago. The Syrian government blames violence on "terrorist gangs" and says some 3,000 members of the security forces have been killed.

Foreign media face severe restrictions on reporting in Syria, and it is hard to verify the claims of either side.

External support

Analysis

By Steve RosenbergBBC News, Moscow

Russia may have vetoed two UN Security Council resolutions condemning President Assad, but Moscow fully supports Kofi Annan's peace mission.

In his talks with the joint UN and Arab League envoy, President Medvedev will make it clear that Moscow's priority is to secure an immediate ceasefire by all sides in the conflict. The Russians, though, have already warned that peace will not be achievable while the Syrian opposition is receiving weapons and political support from outside.

Until now Moscow has been a staunch supporter of President Assad, a long-time Russian ally. There are geopolitical reasons, Russia leases a naval base in Syria. And there are financial concerns, too: the arms deals and Russians investments worth billions of dollars.

But recently there have been signs that Moscow is losing patience with Damascus - senior Russian officials have criticised the Syrian government for dragging its heels on reform and accused it of making numerous mistakes.

Mr Medvedev offered Mr Annan - the envoy for the United Nations and the Arab League - support "on all levels".

"This could be the last chance for Syria to avoid a prolonged and bloody civil war," he said.

"We very much hope your work will end with a positive result."

And at an earlier meeting Foreign Minister Sergey Lavrov "underscored the need to end violence from all sides and establish a broad Syrian political dialogue", a statement said.

"He called on the special envoy to work actively toward that aim with both the authorities and the opposition."

Mr Lavrov urged the international community to co-operate with Mr Annan's mission.

"This means no interference in Syria's internal affairs and the inadmissibility of supporting one side in the conflict," the statement said.

The BBC's Steve Rosenberg in Moscow says that these remarks suggest a very delicate balancing act by Moscow - on the one hand seeking to put pressure on Mr Assad and on the other warning the West not to favour the Syrian opposition.

Meeting Mr Medvedev, Mr Annan said that "Syria has an opportunity today to work with me and this mediation process to put an end to the conflict, to the fighting, allow access to those in need of humanitarian assistance as well as embark on a political process".

He has proposed a six-point peace plan, which calls on government forces to immediately halt the use of heavy weapons in populated areas.

He also wants the armed rebels to halt their attacks - which seems unlikely to happen either, says the BBC's Jim Muir in Beirut.

Image caption
Homs has been relentlessly targeted, activists say

Russia has vetoed two UN Security Council resolutions on the crisis in Syria, but last week, with China, supported a UN statement on the Annan mission.

Our correspondent says that recently there have been signs Moscow is losing patience with Syria. Senior Russian officials have criticised the Syrian government for dragging its heels on reform, and accused it of making numerous mistakes.

Meanwhile US President Barack Obama and Turkish Prime Minister Recep Tayyip Erdogan, meeting ahead of a nuclear security conference in South Korea, said they were looking for ways to bring about change in Syria.

'Protecting army'

The diplomacy comes as a new report by New York based Human Rights Watch (HRW) accused pro-government forces of forcing civilians to march in front of them as they advanced on areas held by the opposition in the northern Idlib province earlier in March.

Videos obtained by HRW from opposition activists showed people dressed in civilian clothes walking in front of armed soldiers and fighting vehicles. Witnesses told HRW it was clear that the move was to protect the army from attack. According to the HRW statement, residents also said children had been placed on tanks and inside security buses.

In another development, the opposition Free Syrian Army and a rival military council have announced that they will work together to co-ordinate all military activity against the Syrian government.